1. Field of the Invention
This invention relates to new aminophenyl alkylenediamines and salts thereof and to their use as developer components in oxidation hair dyes.
2. Statement of Related Art
By virtue of their intense colors and good fastness properties, oxidation hair dyes play a prominent part in the dyeing of hair. Hair dyes such as these contain oxidation dye precursors in a cosmetic carrier. Developer substances and coupler substances are used as the oxidation dye precursors. The developer components form the actual dyes with one another or by coupling with one or more coupler components under the effect of oxidizing agents or atmospheric oxygen.
Good oxidation dye precursors have to satisfy various requirements. They must form the required shades with sufficient intensity during the oxidative coupling reaction. They must be readily absorbed by human hair with no significant differences in this regard between neglected and freshly washed hair. They should be stable to light, heat and the effect of chemical reducing agents especially when in the form of liquid hair dye preparations. Finally, they should not excessively stain the scalp and, above all, should be toxicologically and dermatologically safe to use.
The developer substances conventionally used include primary aromatic amines containing another free or substituted hydroxy or amino moiety in the para or ortho position, diaminopyridine derivatives, heterocyclic hydrazine derivatives and 4-aminopyrazolone derivatives. Useful conventional coupler substances include m-phenylenediamine derivatives, naphthols, resorcinol derivatives and pyrazolones.
Particular importance is attributed to the intensity of the colors formed during the oxidative coupling reaction and to the fastness properties, more especially fastness to light. N,N'-bix-(4-aminophenyl)-ethylenediamines are already known as oxidation dye precursors in hair dyes from U.S. Pat. No. 4,010,200. However, the hair colors obtainable with these developer components in conjunction with standard coupler comounds do not satisfy the stringent requirements of the industry in regard to intensity and fastness properties.